Permanent hydrocarbon reservoir monitoring is a technique where multiple three-dimensional seismic “pictures” of the state of a hydrocarbon reservoir are taken such that a geologist or reservoir engineer may plan the location of additional boreholes for increasing the efficiency of the hydrocarbon extraction and/or may assess the efficiency of the current extraction techniques over time. In some cases, taking multiple seismic pictures of a hydrocarbon reservoir may be referred to as four-dimensional (4D) seismic.
Marine-based permanent reservoir monitoring faces significant challenges that are not faced by land-based permanent monitoring systems. This is particularly true of ocean bottom installations as water depths extend into the 1000 meter range and beyond. In particular, components comprising the sensors and associated data communication systems disposed on the sea floor may be exposed to sea water, high humidity and condensation, and subject to hydrostatic stresses arising in the marine environment.